This removal allows us to remove the `hdrs` target from every module; there
were only two modules that still used it, and they have both been fixed.

E3-1197: Fix possible memory issues

See merge request e3/e3-require!131

This was reported by cppcheck over require's code:
require-ess/src/runScript.c:128:12: error: Common realloc mistake: 'line_raw' nulled but not freed upon failure [memleakOnRealloc]
      if ((line_raw = realloc(line_raw, line_raw_size *= 2)) == NULL)
           ^

Unfortunately realloc can return null, in that case if we use something
like
line_raw = realloc(line_raw, size);
The memory pointed by line_raw is lost.

This was reported running cppcheck over require's code.
require-ess/src/require.c:1002:33: error: Uninitialized variable: &modulediroffs [uninitvar]
               dirname, module, &modulediroffs);
                                ^
require-ess/src/require.c:996:18: note: Assuming condition is false
      if (dirlen == 0) continue; /* ignore empty driverpath elements */
                 ^
require-ess/src/require.c:1002:33: note: Uninitialized variable: &modulediroffs
               dirname, module, &modulediroffs);
                                ^

In function ‘compareVersions’,
    inlined from ‘require_priv’ at .././src/require.c:1025:29:
.././src/require.c:640:9: warning: ‘%s’ directive argument is null [-Wformat-overflow=]
  640 |   debug("require: compareVersions(found=%s, request=%s)\n", found, request);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.././src/require.c:601:28: note: in definition of macro ‘debug’
  601 |   if (requireDebug) printf(__VA_ARGS__)
      |                            ^~~~~~~~~~~
.././src/require.c: In function ‘require_priv’:
.././src/require.c:640:53: note: format string is defined here
  640 |   debug("require: compareVersions(found=%s, request=%s)\n", found, request);
      |                                                     ^~
In function ‘compareVersions’,
    inlined from ‘require_priv’ at .././src/require.c:1025:29:
.././src/require.c:640:9: warning: ‘%s’ directive argument is null [-Wformat-overflow=]
  640 |   debug("require: compareVersions(found=%s, request=%s)\n", found, request);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.././src/require.c:601:28: note: in definition of macro ‘debug’
  601 |   if (requireDebug) printf(__VA_ARGS__)
      |                            ^~~~~~~~~~~
.././src/require.c: In function ‘require_priv’:
.././src/require.c:640:53: note: format string is defined here
  640 |   debug("require: compareVersions(found=%s, request=%s)\n", found, request);
      |                                                     ^~
.././src/require.c:1031:50: warning: ‘%s’ directive argument is null [-Wformat-overflow=]
 1031 |                 printf("require: %s %s may match %s\n", module, currentFilename,
      |                                                  ^~

E3-1186: Allow tests to be run with debug architecture if specified

See merge request e3/e3-require!129

ICS-534: Reverse .substitutions/.templates priority

See merge request e3/e3-require!128

E3-1167: Fix failing doubly-recursive dependency

See merge request e3/e3-require!127

Partial reversion of af57525d

See merge request e3/e3-require!126

The issue is that `COMMANDLINE_LIBRARY` is used by EPICS base to link against
some other libraries; removing this line means that every lib*.so now links
against libreadline.so. This isn't _strictly speaking_ an issue because
`softIocPVA` also ultimately depends on libreadline. However, it is bad
practice.

E3-1135: Remove sequencer rules

See merge request e3/e3-require!125

Add info tags to create a NTTable with module names and version numbers

See merge request e3/e3-require!123

E3-1133: Remove sequencer tests

See merge request e3/e3-require!124

These will be moved to the e3-sequencer module.

Replace dbd expansion tcl script with python script

See merge request e3/e3-require!113

The purpose of this is to remove the dependency on tclx, a non-standard
package.

Fix cross compile

See merge request e3/e3-require!122

EPICS Base changed how it export cross compiled flags. Now we need to
check for "UNIX" and "linux".

E3-1114: Update e3_build docker image version

See merge request e3/e3-require!121

Fix reference for `5.0.0`

See merge request e3/e3-require!120

E3-1112: Move module_VERSION definitions to first make call

See merge request e3/e3-require!119